The answer is light.
One of the factors that affect photosynthesis is light. Without light, the photosynthetic rate is reduced or even stopped which consequently affect algal growth. With increasing depth in the ocean, there is less sunlight present. Still, a<span>lgae have accessory photosynthetic plastids other than the chloroplasts</span><span> that can absorb different light in greater ocean depths. This helps them to maximum use sunlight in such conditions. But, in the end, at some particular depth, they would not be able to survive.</span>
In my opinion, chloroplasts and mitochondria can't live outside the cell now because mitochondria ensure the energy for the cell and the chloroplasts is important for photosynthesis. Just my opinion.
Explanation:
BB=Brown as both are big B's
Bb=Brown as there is a big B
bb=Blue as both are little b's
The answer is ATP molecules being produced, this happens in light and dark.
All of the other options are either directly related to light/photosynthesis or are needed to complete it.